Preheat oven 400 degrees. Sprinkle chicken with seasoning mix. Place 1/2 cup of the potatoes on the center of each 4 large sheets of heavy duty foil (sprayed with pam); top evenly with chicken salsa & cheese.
Bring up foil sides. Double fold top and both ends to seal each packet, leaving room for heat circulation inside. Place in 15x10x1-inch baking pan.
Bake 30 to 35 min. or until chicken is cooked through. Remove packets from oven. Let stand 5 min. Cut slits in foil to release steam before opening. Serve with sour cream.